The basic criterion for the effectiveness of this assembly is the ability to keep the tire perpendicular to the surface at all times, so that it adheres to it with the entire tread width. Of course, this is only possible on smooth and smooth roads, but these are what dominate the racetracks. If the forces acting between the tire and the ground are distributed over its entire width, then, for every centimeter of working rubber there is the smallest load on it, also side. Thus, it deforms slightly and allows for a relatively small so-called. side drift. Such a car drives more confidently than a vehicle, in which the position of the wheels relative to the surface changes with the change of forces, e.g. on the bend. Therefore, the designers of F1, when the regulations allowed them, they tried to increase the contact length of the tires with the track as much as possible, and the use of multi-wheel systems made this possible. The bonus is the improvement of the cooperation between the tires and the track on longitudinal unevenness – with proper tuning of the double suspension. It's easy to imagine, that the tires rolling closely behind each other could overall more accurately adhere to the road under such conditions.
So the aerodynamic gains were not the only ones, which appeared in six-wheeled constructions. It's not hard to see, that Tyrrell's idea was only half right, Williams solution, for the more heavily loaded axle, it had the best theoretical foundations, and Ferrari's attempts at once can be considered senseless.